Leonard andrews



purposes.

@nitrh tstre latent @fitta LEONARD ANDREWS, 0F BIDDEFORD, MAINE.

Letters Patent No. 61,134, elated January l5, 1867.

IMPROVED DRILL.

' IO ALL WHOM IT MAY CONCERN:

Be it known that I, LEONARD ANDREWS, of Biddeford, in the county of York, and State of Maine, have invented certain new and useful improvements in Drills; and I hereby declare the following to be a full, clear, and exact description thereof,` which will enable others to make and use my invention, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 shows a view of an ordinary drill.

Figure 2a View in perspective of one of the horizontal cutters. v

Figure 3, a vertical section of one part of my improved drill, which is employed to enlarge a hole or bore laterally and horizontally. i

Figure 4, a vertical section of the tube and drill used to continue vertically the enlarged bore made by the apparatus shown in fig. 3.

Figure 5 is a side view of iig. 4. i

The object of my invention is to produce a drill by the use of which, when and after a bore has been made for some distance into theaock and stone, by the ordinary means, for the purpose of blasting, it can be enlarged or increased in diameter, and thus continued to the desired depth of the enlarged size. By thus being enabled to shape the bore and to increase it at its lower part, or after it has been made for some distance into `the rock,

much greater e'ects can be accomplished by the same amount of powder or blasting substance than when the hole is of the same size throughout.

My improved drill is composed of two parts, or is employed in the form of two drills, subserving` different In iig. 3 is shown a hollow tube or cylinder, open at the upper end and closed at the lower. At the lower end, however, and hear the bottom ofthe tube, are made two apertures from the outside of the tube, into and communicating with the longitudinal hollow of the tube. These two apertures form together a hole diametrically through the tube and through the hollow thereof. Into these two apertures are placed drills, cutters, or knives, with their edges outward, and, when not pressed out by the means hereinafter described, intended to project no further` than the outside or periphery of the tube or cylinder, or to bc even with its outside. In the hollow of the tube is placed a rod or bar, made at its lower end wedge-shape. This moves up and down in the hollow of the tube. Near the top of the tube a cross-bar is inserted, passingy through spaces in the tube and through a slot in the bar. The slot is long enough to allow the bar to move up and down suciently, and yet to prevent its being wholly withdrawn from thetube, so that the tube can bewithdrawn from the hole in the rock by means of this bar. .A short distance above the bottom of the hollow of the tube is set a ring, through which the bar slides up and down7 and from the ring extend downward two spring-arms which t into niches or grooves in the tops of the horizontal drills or cutters.

a. shows the tube; b the rod or bar; e the cross-bar; d the slot in the rod or bar b; e the ring, with the springsff; g g the horizontal cutters; L the grooves in the same into which the springs t.

The operation of these devices is as follows: When a hole is drilled by a common drill to the depth desired before using myimprovement, then withdraw the drill and sink into the hole the tube and parts shown in igfS. Raise the bar b as far as theslot d will allow, the cutters g g will then be dra-wn within the tube a; then, by striking on the rod b, as when drilling with the ordinary tool, the cutters will be forced outwardly and commence their incision into the sides of the bottom of the hole first made by the common drill. By continuing this, and turning the tube around so as to bring the cutters to all parts' of the interior surfaee'of the hole, it will be enlarged to the extent of the projection of the cutters gg beyond the outside of the tube a, thus forming a circular chamber within the rock, and enlarged beyond the diameter of the hole made by the drill first used, as, foi' instance, such a drill as seen in iig. 1. The horizontal cutters at the top of their edges of contact'with each other are cut away somewhat, so as to flare a little, thus easier to admit the wedge-shaped end of the rod byV which they are, at'cach blow, forced asunder. When the chamber has been thus excavated or out by the part shown in iig. 3, the same is then withdrawn. Into the hole is then inserted the drill shownv in figs. 4 and 5. This consists, first, of a double-edged drill, (shown in section at iig. 4.) This drill is split up for some distance in the stock so that the two cutters or edges slide by cach other as indicated in iig. 5,*and the cutters are coneiner siderably wider thanv the stock of the drill, (see tig. 5.) Over the drill slides a tube, 1, (see iigs.-'1and 5.) The tube is .used to bring together the daring ends ofthe drill so that it may be inserted into the upper and smaller part of the hole, or that part nmdc by ythe commen drill, (iig. 1.) When thus inserted the tube r is withdrawn and the two cutters or edges of the split drill allowed to expend in the chamber beforedcscribed unid out bythe devices shown in iig. 3. The tube 7' hes e collar, s, for convenience of attaching o, rod or :my c) ive'iient means for its withdrawal.' This split or double drill is then used like an ordinary one, by striking upon the upper or outer end and turning it around in the hand after each blow. But the operation of it wit-hin and on the bottoni of the chamber is quite different. The edges ofthe two cutters of thisdrill are inclined or ehnmfered of?, (see u, tig.

5,).so that at each blow upon its upper end these expand n-s well es eut, thus continuing the hele or chamber in the rock at theenlnrged size, und perhaps having :t slight tendency to enlarge it still more. The inclined edges of the cutters throw them apart at every blow of the hammer. Thus the chamber is continued to the desired depth. When the chamber is finished the tube r is once more pushcd'down over the double drill, the two parts thus forced together, und the drill may then be withdrawn from thc'dhole in the rock. Figs. lZ 3, ond 5 :tre of course intended to represent drills ofthe .saine size or diameter. By thus being enabled to drill a blasting-hole larger at the bottom than at the mouth the effect of the blasting material is immensely increased. The powder or other substance used is introduced in the ordinary way. The use of the ring and the two springs'in the tube a is to draw within the tube the two horizontal cutters after they have been forced out by the rod in the tube.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination of the tube a, rod ring end springs eff, horizontal cutters g g, as and for the purposes set forth.

2. The combination of the double'drill, (fig. 5,) constructed es described, with the tube 9', its and for the purposes specified.;

, LEONARD ANDREWS.

Witnesses:

WILLIAM HENRY CLIFFORD,

HENRY C. HOUSTON. 

